Distemper is a contagious disease that can be fatal and presents a variety of symptoms such as coughing, eye mucus, lethargy and vomiting. It can be spread by animals such as dogs, skunks and raccoons.

Antibodies that fight parasites were also found in the cub’s intestine, the report states, but no actual parasites were found.

“We didn’t get the nice definitive answer we had hoped for,” Baker said. “I know it’s hard for the public because they want that closure.”

The second cub’s cause of death turned up inconclusive, Baker said. However, it wasn’t a complete surprise since the baby seemed to have genetic abnormalities from the start. It was born half the size of its brother, appearing almost dwarfed.

“It had a funny-shaped head, and it went on to linger and eventually stop growing,” Baker said.

Both necropsy reports were analyzed by the zoo’s veterinarian, Dr. Steve Robinson, based off tests taken from the animals’ tissue samples sent to the Northwest ZooPath lab in Monroe, Wash.

Overall, zoo staff says it’s not that unusual for first-time mothers among wild animals to lose their babies.

“Sometimes, that’s just how nature works,” Baker said.

Red pandas are arboreal mammals with red fur and bushy tails from the eastern Himalayas and southwestern China, where their populations have been in decline. They typically live 13 to 14 years, Baker said.

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The cubs’ early deaths were disheartening for zoo staff because the two youngsters were the first offspring born after the zoo received a $100,000 gift in 2011 to open a naturalistic red panda exhibit. The animals also garnered much adoration from the public for their cute faces and pretty coats.

“It’s always really hard when we lose an animal at the zoo,” Baker said. “Many of my staff spends more time with the animals here than their pets at home, so it’s like losing a member of the family.”

Since the necropsies were not definitive of any one cause — such as if the mother had dropped the babies from a tree, which would prompt the zoo to add a catch net — changes will not be made to the red panda exhibit.

Further, zoo staff are skeptical that distemper killed the first cub, Baker said, since neither the adult red pandas nor any of the zoo’s other mammals are showing signs of the highly contagious illness.

All the zoo animals get routine physicals at least once a year and any available vaccines for their species.

“We wouldn’t expect to have an animal with a disease here without us knowing about it,” Baker said.

Zoo staff also takes precautions by having the animals rarely leave their exhibits, quarantining new animals for 30 days and not allowing domestic animals in (besides service animals).

The red panda cubs and their parents were not vaccinated for distemper, Baker said, because the vaccine made for dogs can be fatal to the red panda; a version specific to their breed isn’t on the market.

The Charles Paddock Zoo has about 250 animals and is one of the smallest accredited zoos in the nation. It’s part of the national nonprofit Association of Zoos and Aquariums, which exchanges animals between its zoos with the goal of breeding endangered species.

The last time a baby animal died at the Charles Paddock Zoo was two years ago when an antelope-type animal called a duiker was born but only lived one day, Baker said.

Another duiker baby has since been born there and is being prepped to move to another zoo in the association to breed.